Actuating means for foldable implement carriage



D United States Patent [111 3,53

[72] Inventors James J. Bauer, 2,541,964 2/1951 Hennings 172/501XGwinner, and 2,750,724 6/1956 Stephenson 172/456 DennllE. Lludemaun,Lisbon, North 2,828,597 4/1958 Moore 172/456X Dakota 2,995,385 8/1961Lohrman et al. 172/456X [2|] Appl. No. 671,328 3,021,908 2/1962lugosch., l72/456X (22] Filed Sept. 28, 1967 3,428,333 2/1969 Nelson172/456X [45 I Patented 1970 Primary ExaminerRobert E. Pulfrey [73] Amp.By meme f to Assistant Examiner-Alan E. Kopecki Equlpnfent CompanyAttorney-Frederick E. Lange, John J Held, Jr. and Eugene Buchanan, MichL Johnson a corporation of Delaware [54] FOLDABLE ABSTRACT: Theinvention relates to a hydraulically actuated chlmannwing at foldablecarnage for an earth working implement. The car- 7 nage may be foldedfrom a wide field position to a narrow Us. Cltransport or storageposition lt includes features 280/411 prevent damage if movement betweenthe field position and no the transport posifion is attempted theimplement car l, riage in an improper condition It also includesfeatures 280/41 411-1 allow a partial lifting of the implement and, atthe same time, [56] References Cited allow forward movement of thecarriage to thereby clean debris from the implement teeth. The inventionalso includes UNITED STATES PATENTS an improved cable yoke design whichavoids stress in the cable 2.363392 11/1944 Brown 172/501X 'yoke whenthe cables are under tension.

= as w 52 -51 34 T 54 v a a; a 56 2a a a 2a a 2 1 117 Y F6 7 25 .1. n-1| l 5" Patentecl' Nov. 10, 1970 Sheet (Ni MD N H w m 7 A s .v m? mww w2 E,

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Patented Nov, 10; 1970 Sheet RN QN @W N .3 mm Q NN INVENTORS' Jaws J 5A(/32, BY Dam/15' E ZIAIDEMA/VA/ I 4 I'TOPMEV ACTUATING MEANS FORFOLDABLE IMPLEMENT CARRIAGE BACKGROUND OF THE INVENTION The inventionpertains to ground working implements and more particularly to foldabletacks or carriages for such implements. r

, In traversing a field for agricultural purposes, such as plowing,discing, harrowing, mowing and cultivating, considerable time and moneycan be saved by decreasing the number of swaths necessary to cover agivenarea. In other words, the

, wider the swath, within limits, the more economical the operation.Consequently, implement carriages have been designed floor area forstorage. Consequently, some method of breaking down the wide carriageinto a more compact unit, thatis,

: matter.

It is, accordingly, an object to provide a hydraulically actuatedcarriage movable from a field position to a transport position in whicha premature attempt to move the apparatus between field and transportpositions does not cause damage or deformation.

It is also an object to provide a hydraulically actuated implementcarriage wherein reinforcing cables are provided between the tonguesection and the outboard wing beam secfolding the implement from itsfield position to a more compact transport position, must be devised tomake transport and storage feasible. i 7

Various designs for foldable implement carriages have been proposed andexamples of such designs are provided by the following-US. Pats: WordenNo. 2,662,363; Moore No.

2,828,597; and Clark No. 2,944,615. In addition a foldable implementcarriage is disclosed in a US. Pat. application entitled AutomaticHydraulic I-Iarrow Cart filed by Nelson on Apr. 26, 1966 and assignedSer. No. 545,492.

In the prior art, movement from the field position to the transport.position (and vice versa) has been accomplished hydraulically with noprovision for premature actuation of the hydraulic cylinder.Moreparticularly, the hydraulic cylinder has been linked directly to thepivoting transverse beam with no provision made for collapse orcompression of the linkage if actuated prematurely. Thus if thehydraulic cylinder of prior art devices is retracted prematurely withthe carriage in the transport position, considerabledamage results dueto collision'between the implements mounted to the center beam withthose mounted to the wing beams. Either the implements are heavilydamaged and bent or the linkage between the hydraulic cylinder and thepivoting center beam is deformed or broken.

In addition, the prior art carriages either require a manual release ofthe reinforcing bars, cables or chains, which maintain the wing beamsections in their extended field position in alignment with the centerbeam against the tendency to fold back as the carriage is pulledforward, or provide for automatic release through the provision of cablelifting arms. In the case of manual release (Worden, Moore and Clarkpatents) the operator must dismount from the towing vehicle to move fromthe field to transport position, an obvious shortcoming of the design.In the case of automatic release through the provision of cable liftingarms (Nelson application), no provision has been made for relieving thelift arms of compressive forces due to tension in the cables when thecarriage is in the field position. The compressive forces applied to thelifting arms require that the lifting arms themselves as well as theirmountings be designed to carry such forces, which is a factor whichincreases cost.

SUMMARY The present invention solves many of the problems inherent inthe prior art. For example, a telescoping link is provided tions andraised and slackened by means of a cable yoke lift linkage and means isprovided for preventing the transmission of compressive forces from thereinforcing cables to the cable lift arms when the carriage is in thefield position.

It is also an object to provide a hydraulically actuated carriagemovable from a field position to a transport position having reinforcingcables raised and slackened by a cable yoke lift linkage and means forpreventing the transmission of compressive forces from the reinforcingcables to the cable lift arms wherein means is also provided for movingthe carriage from the field to the transport position, soas to lift theimplements carried by the carriage slightly above the ground, withoutactuating the cable lifting arms to thereby allow forward movement ofthe carriage to clean debris and other material from the implementteeth.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the presentinvention and shows the implement carriage in the field position. One ofthe wing beam sections is only partially shown.

FIG. 2 is a plan view of the invention and shows the implement carriagein the intermediate position. The harrow tooth racks which form theimplements associated with the embodiment of the carriage shown are notshown in FIG. 2. One wing beam is only partially shown.

FIG. 3 is a plan view of the invention with the implement carriage inthe transport position. The harrow tooth racks are not shown.

FIG. 4 is a perspective view of the universal joint between the. centerbeam and the wing beams and is shown in the intermediate position.

FIG. 5 is a sectional view taken on the line 55 of FIG. 1 and shows theuniversal joint between the center beam and the wing beam in the fieldposition.

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 1 and shows thehydraulic cylinder and linkage for pivoting the center beam and wingbeams from the field position to the transport position and also showsthe cable lift mechanism. In FIG. 6'the elements are shown in the fieldposition.

FIG. 7 is a sectional view taken on the line 7-7 of FIG. 3 and shows theelements in the transport position.

FIG. 8 is a plan view of the slip clutch which serves in the cable yokelifting linkage.

FIG. 9 is a perspective view of the transport wheels in the transportposition and shows the wheel mounting and means for adjusting the toe-inthereof.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention may be generallyunderstood with reference to FIGS. 1 2 and 3. The foldable carriage hasthree basic positions: the field position shown in FIG. 1, anintermediate position shown in FIG. 2, and the transport position shownin FIG. 3. It includes a tongue section 11, a center beam section 12,and two wing beam sections 13. Tongue section 11 is wheel mounted andincludes a pair of converging frame members 14, hitch l5, and axle 16.Axle 16 is welded to frame members 14 and rotatably supports tonguesection wheels 17.

Center beam section 12 includes center beam which is pivotally mountedwith its longitudinal axis substantially perpendicular to the directionof travel of tongue section 11. Center beam-20 is pivotally mounted bymeans of parallel spaced brackets 21 which are pinned at pins 22 torearwardly extending tabs 23 welded to each of the frame members 14.Thus center beam 20, as will be more particularly described below, maybe pivoted about an axis extending through pins 22.

Wing beam sections 13 include a wing beam 25 which is universallypivotally mounted to center beam 20 at universal joint 26. Universaljoint 26, described more particularly below, allows a universal pivotingof wing beam 25 with respect to center beam 20 except insofar aspivoting of the joint is limited by structure described in detail below.

Both center beam section 12 and wing beam sections 13 include a numberof spaced implement arms 28 which are mounted to center beam 20, in thecase of center beam section 12, and to wing beam 25, in the case of wingbeam sections 13, by means of connectors 29 and backing channel plates30, best seen in FIG. 2. In the illustrated embodiment, harrow racks 31are suspended from implement arms 28. Harrow racks 31 include framemembers 32 which serve as a means for mounting harrow tooth mountingmembers 33 in spaced parallel relationship. Harrow teeth 34 are mountedin spaced relationship in harrow tooth mounting members 33 to serve asground working implements. Each harrow tooth rack 31 is suspended from apair of implement arms 28 by means of chains 35. Coil springs 36 areprovided to minimize swinging movement of each harrow tooth rack 31 whenin the vertical transport position.

It should be understood that harrow tooth racks 31 are but an example ofone implement which may be suspended from implement arms 28. Otherimplements may also be used in connection with the foldable carriagewithout departing from the scope of the invention.

A field wheel 40 is rotatably mounted on the outer end of each wing beam25. As best seen in FIG. 2, field wheel 40 is mounted to wing beam 25 bymeans of mounting plate 41 welded thereto and axle 42 secured tomounting plate 41. Each wing beam 25 is also provided with a transportwheel 43 which is rotatably mounted to wing beam 25 by means of axle 44,in a manner described more particularly below. Field wheels 40 engagethe ground and are used when the implement is in the field position,shown in FIG. 1. Transport wheels 43 do not engage the ground when theimplement is in the field position, but are used when the carriage is inthe transport position shown in FIG. 3.

U-shaped brackets 45 mount a pair of cables 46 to wing beams 25. Cables46 are secured to wing beams 25 by means of U-shaped brackets 45 whichare seated around wing beam 25 and secured thereto by means ofconnectors 47. A clevis 48 is linked with ring 49 and secured by meansof connector 50 to tab 51 of bracket 45 to complete the connection.Cables 46 serve to reinforce the transverse beam, consisting of centerbeam 20 and wing beams 25, at joints 26 when in the field position andwhen lifted, as described more particularly below, do not inhibitmovement of the carriage from the field position to the transportposition when such movement is required.

The carriage is moved from the intermediate to the trans port position(FIGS. 2 and 3) merely by forward movement of tongue section 11. Withtransport wheels 43 in engagement with the ground, forward movement oftongue section 11 causes wing beam section 13 to pivot rearwardly aboutuniversal joints 26 and trail behind tongue section 11 in the positionshown in FIG. 3. The carriage is moved from the transport position tothe intermediate position (FIGS. 2 and 3) by rearward movement of tonguesection 11 which causes spreading of wing beam sections 13 in a manneropposite to the movement from the intermediate to the transportposition. The carriage is moved between the field position and theintermediate position (FIGS. 1 and 2) by means ofa hydraulicallyactuated linkage described below.

The hydraulically actuated linkage may be best seen in FIGS. 6 and 7. InFIG. 6 the linkage is shown in the field position. In FIG. 7 the linkageis shown in the intermediate and transport position. The linkageincludes means for pivoting center beam 20 about the axis extendingthrough pins 22 and it also includes means for raising cables 46 tothereby slacken the cables to allow a rearward pivoting of wing beams 25at universal joint 26.

The linkage for pivoting center beam 20 includes hydraulic cylinder 55which is pinned at one end to cross member 56 which extends betweenframe members 14 of tongue section 11. Hydraulic cylinder 55 is pinnedat the other end to a lifting arm 57 which is pivotally connected toframe members 14 of tongue section 11 atbracket 58 by means of pin 59.Lifting arm 57 is accordingly pivotable in a vertical planeperpendicular to the longitudinal axis of center beam 20 about the axisof pin 59. A telescoping tube 60, which includes two similar halves 60aand 60b. extends from pin 61 at lever arm 57 to pin 62 at center beampivoting bracket 63. Telescoping tube 60 includes sleeve portions 640and 64b. Stops 65a and 6511 are provided to limit the extension of tube60. While stops 65a and 65h limit the extension of tube 60, it should benoted that they do not limit the contraction of compressive movement oftube 60. As hydraulic cylinder 55 is extended and retracted, lifting arm57 pivots about pin 58 and. through telescoping tube 60 and center beampivoting bracket 63, center beam 20 is caused to pivot about the axisextending through pins 22. Thus center beam 20 may be pivoted from thefield position shown in FIG. 6 to the transport position shown in FIG. 7by means ofthe linkage described. In moving from the field position tothe transport position center beam 20 is caused to pivot about the axisextending through pins 22 through an angular distance of about 90 tothereby pivot implement arms 28 from a horizontal plane to a verticalplane.

The telescopic design of tube 60 avoids damage in the event thathydraulic cylinder 55 is retracted with the wing beams 25 in thetransport position (shown in FIG. 3). Without the telescoping capacityof tube 60, premature retraction of hydraulic cylinder 55 with wingbeams 25 in the transport position, would force center beam section 12to collide with wing beam sections 13, and damage could also be done touniversaljoint 26. The telescoping action oftubc 60, however,

dissipates the force applied by the premature retraction of,

hydraulic cylinder 55 and prevents damage. When hydraulic cylinder 55 isproperly retracted, with wing beams 25 in the intermediate positionshown in FIG. 2, center beam section 12 is free to pivot downwardly bygravity as tube 60 moves rearwardly. Center beam section 12 pivotsdownwardly about the axis of pins 22 an angular distance of about 90 tomove from the intermediate position to FIG. 2 to the field position ofFIG. 1.

The hydraulic cylinder 55 also serves as a means for raising andlowering cables 46 to thereby allow rearward pivotal movement of wingbeams 25 about universal joint 26. For that purpose cable yoke best seenin FIGS. 1, 6 and 7, is pivotally mounted to frame members 14 of tonguesection 11 at sleeve brackets 71. Cable yoke 70, includes a pair ofcable lift arms 72 which extend from transverse member 73, pivotallymounted in sleeve bracket 71, to yoke assembly 74. A pair of reinforcingmembers 75 is provided to reinforce the joint between cable lift arms 72and a cross member 73. Yoke assembly 74 includes a rigid cable mountinglink 76 which is slidably mounted to cable lift arms 72 by means ofsleeves 77 which are seated on the ends of cable lift arms 72. Coilsprings 78 are provided and engage sleeves 77 at one end and flanges 79at the other end to movably mount yoke assembly 74 to the ends of cablelift arms 72. Cables 46 are attached to cable link member 76 by means ofclevises 80 and connectors 81. Cable yoke 70 may be pivoted about theaxis of cross member 73 from the field position shown in FIGS. I and 6,to the transport position shown in FIGS. 3 and 7 by means ofu cable yokelift linkage described below.

, With reference to FIGS. 6+8, the cable yoke lift linkage includes abracket attachment 85 formed'integrally with center beam pivotingbracket 63. Bracket attachment 85 serves as a means for transferringrotational movement of center beam about the axis of pins 22 to slipclutch 86 shown in FIGS. 6--8. Slip clutch 86 includes a pair ofangularly offset mounting brackets 87 and 88 on opposite ends thereof.Bracket 87 .is pinned at pin 89 to bracket attachment 85. Bracket 88 ispinned atpin 90 to bracket 91 which is welded to pivoting cross member73 of cable yoke .70. Thus as center beam pivoting bracket 63 is causedto pivot about the axis of pins 22by the action of hydraulic cylinder55, force is applied to slip clutch 86 which is in turn applied tobracket 91 to pivot cable yoke'70 about the axis of pivotingcross'member73 from the field position shown in FIG. 6 to theintermediate or transport position shown in FIG. 7.

Slip clutch 86 may be best understood with reference to FIG 8. Itincludes a pair of exterionclutch plates 93 each designed with an offsetportion 94. The "opposing offset portions 94 provide a camming surface95 which is engaged by a complementary surface 96 formed integrally withclutch rod 97. Clutch rod 97 is welded to bracket 88. A series ofconnectors 98 extend through exterior clutch plates 93 in three pairsand each pair brackets clutch rod 97. Thus clutch rod 97 is free toslide in slip clutch 86 but is not 'otherwise free to pivot or rotatetherein. Springs 99 are provided in association with connectors 98 toapply compressive force on clutch rod 97 through exterior clutch plates93. Springs 99 allow a lateral expansion of the two exterior clutchplates 93. In the event thatcompressive force is applied to slip clutch86 without a transfer of the force through movement of clutch rod 97 theclutch slips. In other words, if slip clutch 86 is actuated and clutchrod 97, due to its inability to move cable yoke 70, cannot move, the camsurface 96 of clutch rod 97 causes lateral expansion of exterior clutchplates 93 as it engages cam surface 95 and the force applied to slipclutch 86 is dissipated.

Stop 100 serves to prevent the transmission of compressive forces tocable lift arms 72. The stop 100 is in the form of an upstanding platerigidly secured to the frame 14. When the cable yoke is in the positionshown in FIGS. 1 and 6, the yoke link 76 is on the opposite side of thestop 100 from the center beam section 12 so that tension in cables 46 istransmitted to the stop 100. Tension in cables 46, due to forwardmovement of tongue section 11 withthe carriagein the field positionshown in FIG. 1, causes coil springs 78 to compress and cable mountinglink 76 engages stop'100. Thus, as pointed out above, the tensile forcein cables-46 is balanced by compression against stop 100 and nocompressive .force (except the slight force necessary to compresssprings 78) is transmitted to lifting arms 72.

lever arm) through slip clutch 86. In such a situation, slip clutch 86serves as a means for dissipating forces which would otherwise cause abreak .'or deformation in the linkage between center beam pivotingbracket 63 and cable yoke 70.

"It should be noted. that the slip clutch 86 has a lag designed intoit-which is'represented by the distance between cam surfaces 95 and 96.Thus clutch rod 97 is free to slide longitudinally of exterior clutchplates 93 for an appreciable distance before cam surface 96' engages camsurface 95. The lag allows a lifting of implement arms 28 from the fieldposition througha small angle without applying force to clutch rod 97(even though -slip clutch bracket attachment 85 rotates about the axisof pins 22). Thus the harrow teeth 34 may be lifted slightly above theground and tongue section 11 can be pulled in a forward direction, withtension in cables 46,

' 6 without applying force to cable yoke 70. By following the foregoingprocedure, the harrow teeth 34 may be cleaned of debris as the carriageis driven forward with the harrow teeth raised slightly above theground.

Iflversal joint 26 may best understood with reference to FIGS. 3-5. Withreference particularly to FIG. 4, universal joint 26 includes offsetbrackets 110 which are welded to center beam 20 and serve to positionpin 1 11 in a vertical position offset rearwardly of the axis of centerbeam 20 when the latter is in the intermediate or transport positionshown .in FIGS. 2---4. Universal joint 26'includes an intermediate block112 which accepts pin 111 at one end and provides a means for mountingbrackets 113 which in ,tum accept pin 114 with its axisextendingperpendicularly to theaxis of pin 111. Brackets 115 are weldedto wing beam 25 to pivotally connect wing beam 25 to universal joint 26at pin 114. Thus, wing beam- 25 may be universally pivoted with respectto center is provided by rib 117. Thus any attempt to pivot wing beam 25about the axis of pin 114 toward plate 116 will result in an engagementbetween the wing beam-25 and plate 116. Plate 7 116 thus serves as astop to prevent such pivotal movement of wing beam 25.

The transport axle may be best understood with reference to FIG. 9.Transport wheel 43 is rotatable on axle 44 which is pivotally mounted towing beam 25 by means of sleeve bracket 120..Sleeve bracket 120 issecured to wing beam 25 by means of connectors 121 and backing plate122. Backing plate 122 extends downwardly, when wing beam 25 is in thetransport position, a distance sufficient to extend beyond axle 44 whichis accommodated by an opening (not shown) in plate 122. Backingplate'122 serves as a means for mounting stop plates 123 which arethreadably engaged with stop screws 124. A bushing 125 rotatably engagesaxle 44 and rests against bearing plate 126. Axle 44, accordingly, maybe adjusted for toe-in by means of stop screws 124. In otherwords, theangle between the axis of rotation of transport wheel 43 and the axis ofwing beam 25 maybe'varied from the perpendicular within a range ofroughly to by the adjustment of stop screws 124. The toe-in adjustmentcontrols the angle between center beam 20 and wing beams 25 when thelatter trail behind center beam 20 with the invention in the transportposition.

OPERATION While the general operation of the present inventionis'apparent from the foregoing description, the more detailed aspects ofoperation are explained below. 2

FIELD TO TRANSPORT POSITION tended telescoping tube 60 pivots centerbeam 20 about the Y axis of pins 22 from the position shown in FIG. 6 tothe position shown in FIG. 7. As center beam 20 is pivoted about theaxis of pins 22, wing beams 25 also pivot about the same axis and fieldwheels 40 are disengaged from the supporting surface as transport wheels43 pivot downwardly to engaged the supporting surface. I-Iarrow racks 31move from the horizontal position shown in FIG. 1 to the verticalposition shown in FIG. 2. i

Simultaneously, compressive force is applied to slip clutch 86 at slipclutch bracket 85. The compressive force is transmitted through slipclutch 86 to bracket 91 welded to pivoting cross member 73 of cable yoke70. Cable yoke 70 is pivoted upwardly from the position shown in FIG. 6to the position shown in FIG. 7 to raise and further slacken cables 46.

At this point the carriage is in the intermediate position shown in FIG.2. As tongue section 11 is drawn forward, wing beam sections 13 pivotabout pins 111 of universal joint 26 and eventually assume the trailingposition shown in FIG. 3. With wing beam sections 13 in the trailingposition, movement from the field position to the transport position iscomplete.

In the event that an attempt is made to move from the field position tothe transport position without first backing up slightly to slackencables 46, slip clutch 86 prevents damage to the cable yoke liftlinkage. A failure to slacken cables 46 leaves cable yoke link 76 inengagement with stop 100 and cable yoke 70 is therefore not free topivot upwardly about the axis of pivoting cross member 73. Accordingly,as hydraulic cylinder 55 is extended and as force is applied to slipclutch 86, that force cannot be dissipated by causing cable yoke 70 topivot upwardly. In the absence of slip clutch 86, a failure in the cableyoke lift linkage would probably occur at bracket 91, a short lever armcompared to the lever arm of cable yoke 70. With the provision of slipclutch 86, however, when cable yoke 70 is not free to pivot upwardly,force applied to slip clutch 86 is dissipated as clutch rod 97 forcesclutch plates 93 laterally apart and slips. Thus, slip clutch 86prevents damage in the event of operator error.

TRANSPORT TO FIELD POSITION To move from the transport position (FIG. 3)to the field position (FIG. 1) the carriage is first backed-up asubstantial distance to spread wing beam sections 13 from the trailingposition shown in FIG. 3 to the intermediate position shown in FIG. 2.Hydraulic cylinder 55 is then retracted to move lifting arm 57 from theposition shown in FIG. 7 to the position shown in FIG. 6. Telescopingtube 60 releases center beam 20 from the transport position of FIGS. 2and 7 and center beam 20 pivots downwardly about the axis of pins 22 tothe position shown in FIG. 6. The downward pivoting of center beam 20 iscaused by gravity acting primarily upon harrow rack 31 suspended fromimplement arms 28 mounted to center beam 20. As center beam 20 pivotsabout the axis of pins 22, wing beams 25 also pivot about the same axis.Field wheels 40, accordingly, are pivoted into engagement with thesupporting surface and transport wheels 43 are pivoted out of engagementwith the supporting surface. As center beam 20 pivots, tensile force isapplied to slip clutch 86 and that force is transmitted to bracket 91which causes cable yoke 70 to pivot downwardly about the axis ofpivoting cross member 73 from the position of FIG. 7 t the position ofFIG. 6. At this point, movement from the transport position to the fieldposition is complete.

In the event that an attempt is made to move from the transport positionto the field position without first backing up a distance sufficient tospread wing beam sections 13 from the trailing position shown in FIG. 3to the intermediate position shown in FIG. 2, telescoping tube 60prevents damage. In the absence of telescoping tube60, the retraction ofhydraulic cylinder 55 would apply a compressive force to center beampivoting bracket 63 and force center beam section 12 to pivot downwardlyabout the axis of pins 22. With the carriage in the transport positionshown in FIG. 3, center beam section 12 would be forced to collide withwing beam sections 13 and harrow racks 31 would be damaged. Moreover,universal joints 26 would be deformed since the compressive force wouldtend to pivot universal joint 26 about pin I14 which is prevented byplate 116. The telescopic feature of link 60 prevents such an occurrencesince it transmits no compressive force to center beam pivoting bracket63 as hydraulic cylinder 55 is retracted. If center beam is not free topivot downwardly about the axis of pins 22 as hydraulic cylinder 55 isretracted, telescopic link 60 merely compresses as sleeve member 64a and64b slide on halves 60a and 60b, respectively, of telescoping tube 60.Thus, the force transmitted by hydraulic cylinder 55 through lifting arm57 is dissipated so that damage to harrow racks 31 and universal joints26 is prevented if, through operator error, hydraulic cylinder 55 isprematurely retracted.

USE

When in use, in the field position, a number of the features describedabove find application. The provision of stop 100 prevents compressionloading of cable yoke 70, since springs 78 compress to allow anengagement between cable yoke link 76 and stop 100 and the force exertedby the cables is transmitted directly to the stop 100.

Also, when in use in the field position, harrow tooth racks 31 may beraised slightly without slackening cables 46. Thus, the carriage may bepulled forwardly with harrow tooth racks 31 raised slightly above theground to clean debris and other material from the teeth. Such cleaningof the teeth is possible due to the lag designed into slip clutch 86.More particularly, cam surfaces 95 of exterior clutch plates 93 arespaced longitudinally a greater distance than the longitudinal distancebetween cam surfaces 96 permitting a limited amount of movement ofcenter beam 20 and clutch plates 93 before any movement of clutch rod 97takes place. Thus center beam 20 may be pivoted to raise implement arms28 and harrow tooth racks 31 a limited amount without causing movementof clutch rod 97 and pivotal movement in cable yoke 70.

Various changes and modifications may be made in the embodiment shownand described without departing from the scope of the invention.

We claim:

1. A foldable carriage for an earth working implement comprising:

a wheel mounted tongue section;

a center beam mounted to said tongue section for pivotal movement abouta horizontal axis transverse to the longitudinal axis of said tonguesection;

a pair of wing beams respectively pivotally mounted to each end of saidcenter beam to thereby define a universal joint at each end thereof;

actuating means mounted to said tongue section and operatively connectedto said center beam for pivoting said center beam about said horizontalaxis through an angular distance of substantially to thereby define afield position and a transport position;

an elongate member mounted to said tongue section for pivotal movementabout an axis transverse to the longitudinal axis of said tongue sectioncomprising a yoke member having means forming an apex at said arcuatelymovable end thereof;

flexible members extending .from the arcuately movable end of saidelongate member to a mounting point on each of said wing beams spacedfrom said universal joint;

linkage means extending between said actuating means and said elongatemember for pivoting said elongate member between a substantiallyhorizontal plane upwardly and rearwardly to thereby define a fieldposition and a transport position of said elongate member;

said flexible members having a length equal to the distance from saidarcuately movable end of said elongate member to said mounting point oneach of said wing beams when said elongate member and carriage are insaid field position;

stop means rigidly secured to said tongue section and engaging theapex-forming means of said yoke member for preventing compressiveloading of said elongate member when said elongate member and carriageare in said field position; and p a wheel mounted to each of said wingbeams at a point spaced from said universal joint for supporting each ofsaid wing beams.

2. The foldable carriage of claim 1 wherein said stop means comprises arigid upstanding member mounted to said tongue section.

3. The foldable carriage'of claim 2 wherein said apex-forming means ofsaid yoke member is yieldably mounted for movement in a direction towardsaid axis transverse to the longitudinal axis of said tongue sectioninto engagement with said stop means.

4. A foldable carriage for an earth working implement com prising:

a wheel mounted tongue section;

a center beam mounted to said tongue section for pivotal movement abouta horizontal axis transverse to the longitudinal axis of said tonguesection;

a pair of wingbeams respectively pivotally mounted to each end of saidcenter beam to thereby define a universal joint at each end thereof;

actuating means mounted to said tongue section and operatively connectedto said center beam for pivoting said center beam about said horizontalaxis through an angular distance of substantially 90 to thereby define afield position and a transport position;

an elongate member mounted to said tongue section for pivotal movementabout a horizontal axis transverse to the longitudinal axis of saidtongue section;

flexible members extending from the arcuately movable end of saidelongate member to a mounting point on each of said wing beams spacedfrom said universal joint;

linkage means associated with said actuating means for pivoting saidelongate member between a substantially horizontal plane upwardly andrearwardly about said horizontal axis to thereby define a field positionand a transport position of said elongate member, said linkage meansincluding a slip clutch comprising a clutch rod disposed between a pairof clutch plates offset mounted, respectively, to said center beam andsaid elongate member, said clutch plates and said clutch rod havingcomplementary, cammed surfaces engagable during operation thereof;

said flexible members having a length equal to the distance from saidarcuately movable end of said elongate member to said mounting point oneach of said wing beams when said elongate member and carriage are insaid field position; and

a wheel mounted to each of said wing beams at a point spaced from-saiduniversal joint for supporting each of said wing beams 5. The foldablecarriage of claim 4 wherein said slip clutch includes means for allowinglimited movement of said center beam before force is transmitted fromsaid center beam to said elongate member.

